Commit Graph

22 Commits

Author SHA1 Message Date
David S. Miller eac56465b8 Merge branch 'batman-adv/next' of git://git.open-mesh.org/ecsv/linux-merge 2011-06-20 12:59:37 -07:00
Antonio Quartulli cc47f66e6b batman-adv: improved roaming mechanism
With the current client announcement implementation, in case of roaming,
an update is triggered on the new AP serving the client. At that point
the new information is spread around by means of the OGM broadcasting
mechanism. Until this operations is not executed, no node is able to
correctly route traffic towards the client. This obviously causes packet
drops and introduces a delay in the time needed by the client to recover
its connections.

A new packet type called ROAMING_ADVERTISEMENT is added to account this
issue.

This message is sent in case of roaming from the new AP serving the
client to the old one and will contain the client MAC address. In this
way an out-of-OGM update is immediately committed, so that the old node
can update its global translation table. Traffic reaching this node will
then be redirected to the correct destination utilising the fresher
information. Thus reducing the packet drops and the connection recovery
delay.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-06-20 11:37:27 +02:00
Antonio Quartulli a73105b8d4 batman-adv: improved client announcement mechanism
The client announcement mechanism informs every mesh node in the network
of any connected non-mesh client, in order to find the path towards that
client from any given point in the mesh.

The old implementation was based on the simple idea of appending a data
buffer to each OGM containing all the client MAC addresses the node is
serving. All other nodes can populate their global translation tables
(table which links client MAC addresses to node addresses) using this
MAC address buffer and linking it to the node's address contained in the
OGM. A node that wants to contact a client has to lookup the node the
client is connected to and its address in the global translation table.

It is easy to understand that this implementation suffers from several
issues:
 - big overhead (each and every OGM contains the entire list of
   connected clients)
 - high latencies for client route updates due to long OGM trip time and
   OGM losses

The new implementation addresses these issues by appending client
changes (new client joined or a client left) to the OGM instead of
filling it with all the client addresses each time. In this way nodes
can modify their global tables by means of "updates", thus reducing the
overhead within the OGMs.

To keep the entire network in sync each node maintains a translation
table version number (ttvn) and a translation table checksum. These
values are spread with the OGM to allow all the network participants to
determine whether or not they need to update their translation table
information.

When a translation table lookup is performed in order to send a packet
to a client attached to another node, the destination's ttvn is added to
the payload packet. Forwarding nodes can compare the packet's ttvn with
their destination's ttvn (this node could have a fresher information
than the source) and re-route the packet if necessary. This greatly
reduces the packet loss of clients roaming from one AP to the next.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-06-20 11:37:24 +02:00
David S. Miller 6018e1183b Merge branch 'batman-adv/next' of git://git.open-mesh.org/ecsv/linux-merge 2011-06-09 14:56:13 -07:00
Marek Lindner ecbd532108 batman-adv: use NO_FLAGS define instead of hard-coding 0
The definition NO_FLAGS was introduced to make the code more
readable and shall be used to initialize flag fields.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-06-09 20:40:38 +02:00
Joe Perches f81c622420 net: Remove unnecessary semicolons
Semicolons are not necessary after switch/while/for/if braces
so remove them.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-05 14:33:39 -07:00
Sven Eckelmann 728cbc6ac1 batman-adv: Use rcu_dereference_protected by update-side
Usually rcu_dereference isn't necessary in situations were the
RCU-protected data structure cannot change, but sparse and lockdep still
need a similar functionality for analysis. rcu_dereference_protected
implements the reduced version which should be used to support the
dynamic and static analysis.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-30 07:39:34 +02:00
Sven Eckelmann 704509b8d4 batman-adv: Calculate sizeof using variable insead of types
Documentation/CodingStyle recommends to use the form

	p = kmalloc(sizeof(*p), ...);

to calculate the size of a struct and not the version where the struct
name is spelled out to prevent bugs when the type of p changes. This
also seems appropriate for manipulation of buffers when they are
directly associated with p.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-30 07:39:33 +02:00
Sven Eckelmann 5f718c2007 batman-adv: Remove explicit casts cast from void* for store
It is not necessary to cast a void* to the pointer type when we just
store it and don't want to do pointer arithmetic before the actual
assignment.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-30 07:39:32 +02:00
Sven Eckelmann 747e4221a0 batman-adv: Add const type qualifier for pointers
batman-adv uses pointers which are marked as const and should not
violate that type qualifier by passing it to functions which force a
cast to the non-const version.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-30 07:39:31 +02:00
Antonio Quartulli 2dafb49d84 batman-adv: rename everything from *hna* into *tt* (translation table)
To be coherent, all the functions/variables/constants have been renamed
to the TranslationTable style

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-08 16:10:42 +02:00
Sven Eckelmann c3caf5196c batman-adv: Remove unnecessary hardif_list_lock
hardif_list_lock is unneccessary because we already ensure that no
multiple admin operations can take place through rtnl_lock.
hardif_list_lock only adds additional overhead and complexity.

Critical functions now check whether they are called with rtnl_lock
using ASSERT_RTNL.

It indirectly fixes the problem that orig_hash_del_if() expects that
only one interface is deleted from hardif_list at a time, but
hardif_remove_interfaces() removes all at once and then calls
orig_hash_del_if().

Reported-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-08 16:10:41 +02:00
Marek Lindner 32ae9b221e batman-adv: Make bat_priv->primary_if an rcu protected pointer
The rcu protected macros rcu_dereference() and rcu_assign_pointer()
for the bat_priv->primary_if need to be used, as well as spin/rcu locking.

Otherwise we might end up using a primary_if pointer pointing to already
freed memory.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-05-01 22:49:03 +02:00
Sven Eckelmann e44d8fe2b5 batman-adv: Disallow regular interface as mesh device
When trying to associate a net_device with another net_device which
already exists, batman-adv assumes that this interface is a fully
initialized batman mesh interface without checking it. The behaviour
when accessing data behind netdev_priv of a random net_device is
undefined and potentially dangerous.

Reported-by: Linus Lüssing <linus.luessing@ascom.ch>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:52:09 +01:00
Marek Lindner e6c10f433a batman-adv: rename batman_if struct to hard_iface
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:52:06 +01:00
Marek Lindner 4389e47af8 batman-adv: rename global if_list to hardif_list
Batman-adv works with "hard interfaces" as well as "soft interfaces".
The new name should better make clear which kind of interfaces this
list stores.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:52:05 +01:00
Marek Lindner 39901e7162 batman-adv: separate ethernet comparing calls from hash functions
Note: The function compare_ether_addr() provided by the Linux kernel
requires aligned memory.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:50:14 +01:00
Marek Lindner ed75ccbe26 batman-adv: Correct rcu refcounting for batman_if
It might be possible that 2 threads access the same data in the same
rcu grace period. The first thread calls call_rcu() to decrement the
refcount and free the data while the second thread increases the
refcount to use the data. To avoid this race condition all refcount
operations have to be atomic.

Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:50:07 +01:00
Simon Wunderlich a4c135c561 batman-adv: protect bonding with rcu locks
bonding / alternating candidates need to be secured by rcu locks
as well. This patch therefore converts the bonding list
from a plain pointer list to a rcu securable lists and references
the bonding candidates.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
2011-03-05 12:50:01 +01:00
Sven Eckelmann 64afe35398 batman-adv: Update copyright years
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-01-31 14:57:12 +01:00
Sven Eckelmann fb86d7648f batman-adv: Remove declaration of batman_skb_recv
batman_skb_recv can be defined in hard-interface.c as static because it is
never used outside of that file.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-01-31 14:57:11 +01:00
Sven Eckelmann c6c8fea297 net: Add batman-adv meshing protocol
B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is a routing
protocol for multi-hop ad-hoc mesh networks. The networks may be wired or
wireless. See http://www.open-mesh.org/ for more information and user space
tools.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-16 13:44:24 -08:00